Links items' effects to familiar. Assuming that this works the same as the previous Skill Junction, this means the following is probably true (but needs to be checked!):

Weapons don't do anything that would qualify for Junction, e.g., MH's HP leech.

100% of most of the positive effects are passed on, 150% for ST and DX, and some of the negative effects are fully blocked. ST and DX penalties are blocked by Junction, but some other penalties are not, for example, the -5 UC for using a Shield. To get the full effect for ST and DX the junction minion needs to have a base of 100 ST and DX.

Effects apply to minion and familiar, but only the familiar's end is modified by Junction.

The effect of a Helm of Clearsight transfers.

Using a MgS with an AoJ and a DD familiar will cause the familiar's DD spell level to become 0.

Junctions skill on the minion wearing the amulet to the familiar. (It is suspected that this is currently not working correctly.)

Best used on any strategy that uses a Familiar type tattoo.

Naming gives no bonus.

AC from minion also transfers to the familiar without being affected by encumbrance

All amulets have been changed (13th of March 2009) [2] to +10 versions which grant 100% junction effect. For the brief period during the beginning of their introduction, they were randomly spawned between +1 and +10 (non forgeable, non blacksmithable), only granting 10% junction per level.